Effects of VEGFR-3 phosphorylation inhibitor on lymph node metastasis in an orthotopic diffuse-type gastric carcinoma model

M Yashiro, O Shinto, K Nakamura, M Tendo, T Matsuoka, T Matsuzaki, R Kaizaki, M Ohira, A Miwa and K Hirakawa

  1. 1Department of Surgical Oncology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
  2. 2Oncology Institute of Geriatrics and Medical Science, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
  3. 3Drug Discovery Research Laboratories, Kyowa Hakko Kirin Co., Ltd., Mishima, Shizuoka, Japan

Correspondence: Dr M Yashiro, Received 3 June 2009; Revised 10 August 2009; Accepted 12 August 2009.

Abstract

Background:

Vascular endothelial growth factor receptor-3 (VEGFR-3) signalling mediates lymphangiogenesis and lymphatic invasion; however, the effect of VEGFR-3 inhibition on the lymph node (LN) metastasis remains unclear. The aim of this study is to clarify the benefit of a VEGFR-3 inhibitor Ki23057 for LN metastasis.

Methods:

Ki23057 was administered orally to gastric cancer models created by orthotopic inoculation of diffuse-type gastric cancer cells, OCUM-2MLN. The effects of Ki23057 on lymphatic vessel invasion, lymphatic vessel density, and VEGFR-3 phosphorylation were examined by immunostaining or immunoblotting.

Results:

Ki23057 inhibited the autophosphorylation of VEGFR-3, with IC50 values of 4.3 nM in the cell-free kinase assay. Murine gastric cancer models created by the orthotopic inoculation of OCUM-2MLN cells showed the diffusely infiltrating growth and frequently developed LN metastasis. The oral administration of Ki23057 significantly (P<0.01) reduced the size of orthotopic tumours and the number of the metastatic LN in gastric cancer models. The degree of lymphatic invasion and lymphangiogenesis was significantly (P<0.05) lower in the gastric tumours treated by Ki23057. Ki23057 inhibited the phosphorylation of VEGFR-3 of lymphatic endothelial cells in gastric tumours.

Conclusion:

The inhibition of lymphangiogenesis targeting VEGFR-3 phosphorylation is a therapeutic strategy for inhibiting LN metastasis of diffuse-type gastric cancer.

Keywords:

diffuse-type gastric carcinoma, lymph node metastasis, orthotopic gastric cancer model, phosphorylation inhibitor, vascular endothelial cell growth factor receptor-3

British Journal of Cancer (2009) Published online 29 September 2009